Question

I met a weird issue. please see the code I paste below.
in myclass I have a @property datef.
I can set get the property;
but when I make myclass inherit from mybase,
I cannot set the property any more.
Why?

class mybase(object):
    pass

class myclass(mybase):
    @property     
    def dataf(self): return 1

var = myclass()
print var.dataf
var.dataf = 33
print var.__dict__

Answer 1

You need to define property getter and setter:

class mybase(object):
    pass

class myclass(mybase):
    def dataf_get(self): return getattr(self, "_data_f", None)
    def dataf_set(self, value): self._data_f = value
    dataf = property(dataf_get, dataf_set)

var = myclass()
print var.dataf
>> None
var.dataf = 33
print var.dataf
>> 33
print var.__dict__
>> {'_data_f': 33}